I didn't read the doc because I would have way too much to argue with to fit in a post.

Environment:

Animals eat crops. Any crop issue is multiplied by animal agriculture and then the animals themselves causing damage and then being killed. Your only argument would be "grass fed" beef.

• Cows are only around 5% efficient at converting calories from plants, so even the smallest amount of crops fed puts you in the negative.
• They are sent to the feedlot a few months before slaughter to fatten up (way more than 5% of life).
• Usually some supplemental feeding, especially in inclement weather.
• Can be feed plant milk at the beginning.
• The increased land needed alone causes more deaths:7.5 death/acre grass fed vs 15 death/acre crops, but you need more than 2x acres grass to get equal calories to the crops.

Not to mention the methane and every other animal not producing methane would need crops. Also, grass fed is not a sustainable solution to feed the planet as well as killing innocents intentionally vs accidental in a defensive way. Every way you twist it, just nope.

Also, antibiotic resistance is almost solely from animal agriculture.

Here is the math on grass fed and field deaths. At best, and using sources in favor of grass fed, you break even in field deaths. Realistically you use more resources and kill more.

Here is some explanation on the stringent requirements to be more efficient at calorie production with beef.

Here is a study explaining the food loss, protein conversion, carrying capacity, etc. for a vegan diet.

Meat is the most nutrient-dense food one can eat, and is the biologically optimal food for humans - it is what we are best adapted to consume.

If true, so what? Doesn't mean it is the healthiest in outcome.

Saturated fat is much easier to get from animal products. Trans fats are always in animal products (only small amounts found in processed cooking oils). Cholesterol is only in animal products and increased risk of heart disease.

Lower all cause mortality for a consistent vegan diet.

And this.

Largest dietetics association in the world says "Vegetarians and vegans are at reduced risk of certain health conditions, including ischemic heart disease, type 2 diabetes, hypertension, certain types of cancer, and obesity. Low intake of saturated fat and high intakes of vegetables, fruits, whole grains, legumes, soy products, nuts, and seeds (all rich in fiber and phytochemicals) are characteristics of vegetarian and vegan diets that produce lower total and low-density lipoprotein cholesterol levels and better serum glucose control. These factors contribute to reduction of chronic disease." Every other dietetics association has come to similar conclusions. The same goes for individual dietitians.

if the above two are true

Environment isn't true for sure just on simple math. At best vegan is as healthy as omni. Most likely, vegan and fish are about the same, and only other animal product increases all cause mortality.

significantly poorer health outcomes for the populace (including early death, but also poor quality of life)

Not true and the only way to justify killing thousands of animals is if it was necessary to survive, not just improve quality of life slightly.

continued environmental degradation, loss of biodiversity, and unsustainability of food production.

You need more food to produce animal products.

Even if these were true, still not ethical unless you would do the same for humans, as in breed to kill. Assuming you think it is a moral obligation to not breed to kill humans, why in;t this so for animals.